The Pizza Lab: Homemade Philadelphia Tomato Pie

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[Photographs: J. Kenji Lopez-Alt, except where indicated]

As a universal lover of nearly all things pizza (I say nearly because, dear Chicago readers, I'm afraid I just can't get into that stuff you've got. Sorry.), I'm often surprised and even more often captivated by the width and breadth of pizza styles that we've got in this fair country of ours. We may not have invented pizza, but when it comes to reinventing and making it our own, nobody—not even the Italians—knows sauce-covered-pies like we do.

To call Philadelphia-style Tomato Pie (not to be confused with a Trenton Tomato Pie) a pizza is not much of a stretch. It fits most people's definition—relatively flat bread, tomato, a bit of cheese, cut into flat slices before serving—but at the same time, it's a beast entirely unto itself. Saucy focaccia might be a more apt description, though it has a far finer, softer crumb than any focaccia I've seen.

Philadelphia native and Slice Correspondent Hawk Krall probably does a better job than anyone of explaining the appeal of Tomato Pies:

Old fashioned Philly Tomato Pie is a bit hard to explain to outsiders. It's distinctly different from everyday pizza—the best Tomato Pies come room temperature from old-school neighborhood bakeries rather than hot from a pizzeria. No toppings and no cheese, save for a scant shake of Romano or Parmesan. For many who grew up in the area, this simple bakery style pie says "Philly" more than any other style of pizza.

The rumor is that Tomato Pie got its starts as a means to use up leftover hoagie roll dough by piling it into a greased square sheet tray, topping it with a sweet, thick tomato sauce, baking it up, and serving it by the slice at room temperature. As a lover of both square pies and cold leftover pizza, this seemed like something right up my alley. The real question is: is it possible to create real Philadelphia-style Tomato Pie in a New York kitchen?

The Sauce

Unlike a fresh, lightly cooked Neapolitan sauce, Philadelphia Tomato Pie sauce is thick, heavy, smooth, thick, and sweet, and comes heavily seasoned with herbs. As I learned from my research into New York-style pizza sauce, there are a couple keys to building great flavor into a cooked-down tomato sauce.

First rule:use a mixture of olive oil and butter. It's a trick I cribbed from Marcella Hazan's tomato sauce in which she cooks tomatoes with butter and a whole onion split in half. Simmering the onions whole (in this case I ended up going with shallots, though onions would work fine) instead of chopping and cooking them gives you a smoother, rounder flavor and improved texture when you're going for a relatively smooth sauce. Butter, apart from adding its own milky flavor, helps to smooth out the flavor of the sauce, shaving down the sharp edges of the tomatoes and making the whole thing richer, fuller, and sweeter.

Herbs, plenty of garlic, and a pinch of red pepper are also essential to the flavor profile, so I started my sauce by sautéing them in the fat to help release and develop their flavors.

You often hear cooks of a certain ilk say that dried herbs are useless and only fresh herbs should ever be used. These are probably the same kinds of cooks who call mayonnaise aïoli, and they should largely be ignored. When it comes to savory herbs that are grown in hot, dry environments, the dried version will do just fine.

See, herbs like oregano, marjoram, savory, sage, rosemary, and bay leaf (amongst others), grow in hot, arid environments, so the flavorful compounds locked inside their leaves have to naturally be more resistant to evaporation or breaking down under high temperatures. Thus, even when dried, they are able to retain flavor far longer than more delicate herbs like, say, basil, parsley, tarragon, or chervil.

The key to using these types of dried herbs is to just make sure to cook them long enough to allow them to release their flavor into the sauce, and to soften them in texture. So, sautéeing them right from the beginning in the olive oil/butter mixture is a good idea. Sprinkling them on top of the pie in the end is not.

After cooking down the aromatics, I added tomatoes (in this case, I went with whole canned tomatoes that I roughly pureed in the blender), along with the shallots, and let it go for a long simmer. All the sauce needed in the end was a pinch of salt and a bit of sugar*.

*I know you purists will cringe at the addition of sugar, but that's just the nature of Philadelphia Tomato Pies, and in this case I think it works. You can stay silent or go sit in the corner with the fresh-herb-only brigade.

With a good sauce recipe on hand, I started baking off a few sample pies to refine my dough.

The Dough

First things first: Philadelphia Tomato Pie is not thin-crust pizza. It should be thick—Sicilian thick—at about an inch tall, stretching all the way across the pan filling in all four edges and corners. Not enough dough to rise into your pan, and you end up with this problem:

Sauce in order? Yep. Sprinkle of Romano? Check. Nice, 1/8th-inch thick layer of soft dough at the crust-sauce interface? Absolutely. But thin patches and dimples that threaten the structural integrity of the crust? Yeah, we've got that too.

In order to make sure that the dough rose to a good height, I had to use a full 500 grams (about 17.5 ounces or 3 1/2 cups) of flour. Bread flour with its high protein content and potential for high gluten development (that's the stretchy network of proteins that gives structure to bread), is a common choice for pizza dough, but in this case, I preferred the softer texture and tighter crumb that all-purpose flour produced.

Using a basic recipe of flour, water, salt, yeast, and a touch of olive oil, I experimented with a few different mixing methods, ranging from the simplest (kneaded in a stand mixer or food processor, allowed to proof once, stretched, and baked), to the just-as-simple-but-more-time-consuming (mixing dough, letting it proof overnight under refrigeration, stretching and baking the next day). The latter method was far superior, giving the dough ample time for flavor development and allowing it to build up nice structure as gluten slowly developed overnight.

I tried simply reducing the amount of water used, all the way down to 50% hydration (at this point, you basically need a rolling pin to get the dough to stretch out properly)

Also essential was to stretch the dough into the greased baking sheet and allowing it to rise inside the pan in order to acquire the height it needs. Tomato Pies have a pretty distinct raised edge. To form them, I found the side of a greased hand was the best tool:

Though Hawk tells me that his intelligence network has informed him that most bakeries grease their pans with plain old vegetable oil, as a lover of olive oil, I decided to swap out the vegetable oil for extra-virgin olive oil instead (you are free to use vegetable if you prefer a more authentic experience).

I knew my dough recipe would need some work, but for now, I decided to sauce up a sample batch and see how it turned out.

First lesson learned: this is not a Neapolitan pie, and super-high heat is not necessary. With higher heat, you end up with spottier cooking. Your dough develops dark, charred spots, bigger bubbles, and a thinner, crisper crust. For a New York pie or a Neapolitan pie, these are a good thing. A Philadelphia Tomato Pie, on the other hand, should have even, golden brown coloring with a slightly thicker, crunchier top crust, and a very light blond, almost pale underbelly.

A Neapolitan pizza cooks at 900°F for about 90 seconds. A New York pie cooks for about 10 to 15 minutes at 550 to 600°F. For a Philly Tomato Pie, A relatively low temperature oven—say, 450°F— and a longer cook time—about 20 minutes—allows for more even coloration and more significant crust formation.

Another lesson: pour on the sauce, and pour it on thick. A Neapolitan pizza gets a thin, thin veneer of sauce. New York pies can ladle it on a bit thicker, but sparing is still the word to keep in mind. With a cheese-less Philadelphia pie, there's no protection to keep the sauce from over-evaporating during baking, causing a problem I like to call PPB (that would be Pizza Pattern Baldness). In the worst cases of under-saucing, you get not only bald spots, but great cracks and rifts that threaten to tear the world of pizza sauce right in two.

Alright, that's perhaps a bit of hyperbole, but the lesson learned is the same: use more sauce.

With that in order, on to perfecting the crust:

Good Hydration

Anybody who's worked with bread knows that the more water you add to a dough, the larger the bubbles and holes in the resultant dough will be. As a general rule, if you want a denser, tighter crumb, just use a bit less water.

On the other hand, it's a tradeoff: less water also means less chewiness, and a tougher loaf. For my normal focaccia-style pizza dough recipe, I add 350 grams of water per 500 grams of flour—that's the equivalent of a 70% hydrated dough, in baker-speak (that is, the water added weighs 70% of the total weight of the flour). At that hydration level, you end up with a very wet dough that takes a bit of practice to work with (it nearly flows like a soup), but produces a very nice, open, bubbly crumb structure, like this:

Excellent for focaccia, not so great for Tomato Pie.

I tried simply reducing the amount of water used, all the way down to 50% hydration (at this point, you basically need a rolling pin to get the dough to stretch out properly), but it was a bust. Less water gave me a denser crust, but it made the pizza unpleasantly dense—the crust would get the texture of raw dough as you chewed on it.

The key to tight structure while maintaining good softness and flavor? Fat.

See, enriched doughs (that is, doughs that are fattened up with ingredients like oil, butter, milk, or egg yolks) pretty much universally have a tighter, denser crumb than lean doughs. It has to do with the formation of gluten. When you knead dough, long strands of water soluble proteins called glutenin and gliaden will line up and link together, eventually forming a tough, stretchy, web-like matrix known as gluten. When you add some fat to that mix, it can coat strands of proteins, preventing them from linking up too tightly.

The result is a gluten matrix that's not quite as stretchy; and, without the ability to stretch, you end up with smaller bubbles. The key to adding fat? Balance. Dough is a balancing game between the proteins in the flour, the water, and the fat.

I'd already been using a touch of olive oil for flavor, after a few more test runs, I finally came up with a balance I was happy with, and it required quite a bit more oil than I'd been using.

65% water and 6% extra-virgin olive oil (that's about 2 1/4 tablespoons for 3 1/2 cups of flour) proved to be just right.

Topping Her Off

With a great crust, cooking method, and sauce in order, only one thing remained, and it was the hardest part of all: wait until the darn thing cools to room temperature before adding the cheese.

I can tell you, the urge to rip straight into one while it's hot out of the oven is overwhelming.

Then again, if you're into the whole cool-pie thing, this is hands down the best type of pizza to eat cold. It stays tender, doesn't toughen up, the sauce is flavorful and highly seasoned, enough that even when cool it packs a punch, and the thin dusting of Pecorino (one of the strongest cheeses out there) ties the whole thing together.

With a hungry wife to feed and not enough time to cook, it's also nice to have a pizza that I can bake off in the morning or evening and have stick around under a foil cover for a day or two, ready to be eaten without even the need to reheat.

That said—and Hawk, please don't come after me—I must admit that the pie is perhaps even more killer when it's hot.